1. Field of the Invention
The present invention relates to an optical lens assembly, and more particularly, to a compact optical lens assembly applicable to electronic products.
2. Description of the Prior Art
The demand for compact imaging lens assemblies has grown in recent years as the popularity of portable electronic products with the photographing function has increased, and the sensor of a general photographing camera is none other than CCD (Charge Coupled Device) or CMOS (Complementary Metal-Oxide Semiconductor Sensor). Furthermore, as advances in manufacturing technology of semiconductor have allowed the pixel size of sensors to be reduced, and the resolution of compact imaging lens assemblies has gradually increased, there is an increasing demand for compact imaging lens assemblies featuring better image quality. A conventional compact imaging lens assembly for portable electronic products, such as the one disclosed in U.S. Pat. No. 7,145,736, is of a triplet type comprising, in order from the object side to the image side: a first lens element with positive refractive power; a second lens element with negative refractive power; and a third lens element with positive refractive power. However, as modern electronic products are becoming even more compact and powerful in functionalities, the demand for imaging quality will definitely increase. Therefore, the three-element lens assembly has become insufficient for a high-end imaging lens module, such as camera units on current high-end smartphones.
U.S. Pat. No. 7,660,049 has disclosed a lens assembly comprising four lens elements, wherein the first lens element has negative refractive power and is meniscus in shape so that the aberration and astigmatism of the optical system can be effectively eliminated to improve the image quality. Such arrangement of optical elements, however, will results in a longer total track length as well as the sensitivity of the positive second lens element remains excessively high.
In the light of foregoing, a need exists in the art for an optical lens assembly that features better image quality, maintains a moderate total track length and is applicable to compact portable electronic products.